The present invention is directed to integrated circuits. More particularly, the invention provides a system and method for two-level protection. Merely by way of example, the invention has been applied to a power conversion system. But it would be recognized that the invention has a much broader range of applicability.
Generally, a power conversion system includes one or more mechanisms for over-current protection so that the system can be protected against an excessive current if the output load exceeds a limit. For example, if a high output capability is needed for the power conversion system during a short period of time to drive a load (e.g., a printing system, a capacitive load) and/or for over-clocking of a central processing unit, a current threshold for over-current protection may need to be set at a high magnitude in order to provide such high output capability. But when the power conversion system provides the high output capability, the system current may become so high as to cause over-saturation of the system, even though the system current has not yet reached the high current threshold and the over-current protection is not yet triggered. Then, the power conversion system may become over-heated and thus fail.
Hence it is highly desirable to improve the techniques of protecting power conversion systems.